OBS engine nano rebuildable drip atomizer is made of 304 stainless and used POM drip tip. Nano tank inherited the engine atomizer family's top airflow good genes. Top side filling is very convenient, you just need to rotate and pull up the top cap and refill liquid. You will enjoy coutinual big vapor experience because its 5.3ml large capacity. The single post build deck can match with any heating wire in market.